1. Technical Field
The present invention relates to an automated trim tab control system for use on a motorized marine vessel and, more particularly, to an electro-mechanical circuit that will automatically cause the trim tabs to be fully retracted upon causing a capacitor in the circuit to discharge. The capacitor is caused to discharge by either opening a switch connected between the capacitor and the electrical power source, or by grounding a portion of the circuit by shifting the engine into reverse gear. The present invention also relates to a tab control system providing a plurality of control buttons wired to the switch, or alternatively a plurality of the switches, the control buttons or the switches being mounted in multiple locations throughout the craft, including at the vessel's main control panel, each button or switch being configured to facilitate operation by foot or by hand, depending upon its location.
2. Background Art
It is well known in the power boat manufacturing industry to employ devices on marine vessels to allow the operator to selectively trim the attitude of the craft to accommodate various conditions as the boat is powered through the water. One of the more common of these devices uses substantially planar tabs adjustably attached to the rear of the hull of the vessel below the water line. When the boat is propelled forward, the bow can be raised or lowered in relation to the stern by adjusting the orientation of the tabs accordingly.
While adjustable trim tabs have proven to be an effective method for controlling the attitude of marine vessels, improvements to the systems used to control the tabs are needed. The Bennett et al U.S. Pat. No. 5,113,780, which discloses an automatic boat trim tab control device that includes electronic circuitry that is responsive to the removal of ignition power from the boat engine for causing the trim tabs to be fully retracted, provides one such improvement. The Bennett et al device serves as a safeguard against boat operator negligence by assuring that the tabs will be fully retracted before the boat is loaded onto a trailer or lifted by a fork lift, two situations where the tabs will likely incur damage if they are not fully retracted. It further reduces the area of the trim tab adjusting means that is left exposed to marine growth when the boat is stored in the water.
Despite the improvement provided by the Bennett et al device, the need for further improvements remains. One such need is for an automated control system that provides more hands-free adjustment of the tabs. During initial acceleration of the boat, it is frequently desirable to extend the tabs so as to prevent the bow from lifting out of the water. This prevents the propeller from riding too deep in the water and causes the forward thrust to be delivered more efficiently. However, moments after initial acceleration, it may become necessary to retract the tabs fully to prevent the bow from being driven into the water. Until now, to achieve trim tab retraction the operator has had to manually throw a tab adjusting switch for the duration necessary to achieve full tab retraction (approximately twenty seconds) for each tab that was extended. Typically, a vessel equipped with trim tabs has a port and starboard tab. Thus, to simultaneously retract the tabs requires the operator to simultaneously throw the respective tab adjusting switches for up to twenty seconds, thereby leaving the operator unable to simultaneously adjust steering and propulsion of the vessel. Such lack of control presents obvious potential hazards.
A second needed improvement is for a tab control system that would prevent damage to the trim tabs and maximize engine propulsion efficiency and control when the boat is propelled in the rearward direction, regardless of operator alertness. Until now, it has been up to the vessel operator to remember to retract the trim tabs before propelling the boat in reverse. Failure to do so will cause the tabs to encounter high water pressure in a manner not intended by their design. This hydraulic pressure will cause the trim tabs to act as a brake to the rearward propulsion of the boat, thereby impeding smooth navigation of the vessel in the rearward direction, as well as greatly detracting from engine efficiency. Furthermore, if the boat is propelled in the reverse direction with sufficient force, the hydraulic pressure encountered by the trim tabs may damage the tabs, the mechanical hardware affixing the tabs to the hull, the mechanical hardware used to adjust the orientation of the tabs, and/or the electrical circuitry used to activate the adjusting hardware.
Another needed improvement is for a tab control system that can be operated from locations on the boat remote from, and in addition to, the main control panel location. Such a system could allow boat passengers to be able to trim the vessel attitude, thereby freeing the boat operator to concentrate on more pressing navigational matters. Furthermore, such an improvement would provide the vessel operator with more versatility by enabling the operator to control the vessel attitude even when the operator is at locations in the boat remote from the control panel.